Boolean intersect two 2d extruded bezier curves (non destructive)
Well I found some time to try and code an add-on that will do what I think you are talking about. It is found here, or on this thread. To use:

Install

Add Curve, and Bevel

Add a mesh object like a cube

Go to the modifiers tab and select the curve's name under the Curve Conversion part

Click Update Mesh


What it does is automatically converts the curve to a mesh and replaces the current objects data. It will respect any materials or modifiers added before you press Update Mesh. The Respect Scale option copies the scale from the curve. So if you scale the curve up the mesh object does the same.
Let me know if this is what you were talking about.
EDIT: Check Blender Artist thread to get updated instructions as they come